Like Autodesk123D (old) and Fusion360 where you can select a surface of one model, then select a surface on another model and the First model will snap centered to the Surface of the second model.
Simplyfy3D already does this to the build plate, we just need an option to select a second surface to perform this on instead of the build plate. This will make assembling scenes to print so much easier if we could do this in slicer.
Thank you